What is a sales invoice?

A wholesaler delivers a pallet to a shop and an installation firm finishes a job. Both then send a sales invoice. Only with that invoice does the debt from the customer appear in your books, and only then do you and your customer start to think about when payment will arrive.

What is on it? Your details and the customer's, an invoice number and date, a description of what you delivered, the amount with and without VAT, the payment terms and your bank account number. Invoices carry a running number so that they are easy to trace. What else is required depends on the situation. Ask your accountant if in doubt.

An invoice is only right when the work behind it is right. What you invoice must match what was ordered and delivered, at the agreed price and discount. Differences lead to arguments and late payment. That is why it pays to enter order data once and reuse it rather than retype it.

After sending, you follow up on payment. When money arrives, you link it to the invoice through payment matching. If there was an error, you do not correct it by changing the invoice but by issuing a credit note.

If you want to give a customer an overview of the amount to be paid in advance, for example for a prepayment, you can use a pro forma invoice. It is not a real invoice and does not create a debt. The sales invoice itself follows after delivery.